What is the test for a claim under Section 1983 of the Eighth Amendment against a prison officer for failing to protect an inmate from physical abuse?

To state a claim under Section 1983 for a violation of Eighth Amendment rights, a plaintiff must allege: (1) that a right secured by the Constitution or laws of the United States was violated and (2) that the alleged violation was committed by a person acting under the color of state law. See West v. Atkins, 487 U.S. 42, 48 (1988); McDade v. West, 223 F.3d 1135, 1139 (9th Cir. 2000).

To establish a violation of a prison official's duty to take reasonable steps to protect inmates from physical abuse, the prisoner must establish that prison officials were "deliberately indifferen[t]" to serious threats to the inmate's safety. Farmer v. Brennan, 511 U.S. 825, 833-34 (1994). The deprivation alleged must be "objectively, 'sufficiently serious'" and the prison official must be subjectively "deliberately indifferent" to the inmate's safety. Id. at 834. To demonstrate "deliberate indifference" to a serious threat to the inmate's safety, the prisoner must show that "the official [knew] of and disregard[ed] an excessive risk to inmate . . . safety." Id. at 837.